Magnetic levitation systems, often called MAGLEV systems, use magnetic fields to levitate and propel a vehicle over a stationary guideway. Specifically, a current is passed through linear synchronous motor (LSM) windings mounted on a track. This current then interacts with a magnet system mounted on the vehicle to generate propulsion of the vehicle. In order to use the LSM windings to accelerate, decelerate and maintain the vehicle at a constant speed, the phase, amplitude and frequency of the current in the LSM windings must be accurately controlled at all times. Specifically, the propulsion current passing through the LSM windings must be synchronized with respect to the position of the vehicle. Therefore, it is extremely important that the position of the vehicle with respect to the track, and the windings therein, be monitored and communicated to the propulsion control system.
Currently, optical sensors exist for determining the location of MAGLEV vehicles relative to their guideways. However, these optical sensors require use of a “piano key” tape that must be maintained clean, dry and in good condition. Otherwise, accidental pulses are generated by the optical sensors which can lead to errors in LSM magnet flux position detection that will result in erroneous operation of the propulsion of the MAGLEV vehicle.
In light of the above, it is an object of the present invention to provide systems suitable for the purposes of determining the position of a vehicle over a guideway that are stable and accurate. It is another object of the present invention to provide a vehicle position determining system that provides passive sensing. It is yet another object of the present invention to provide a MAGLEV vehicle position sensing system that communicates the location of the vehicle through the propulsion windings to a system controller. Still another object of the present invention is to provide a MAGLEV vehicle position sensing system that can be used to optimize the interaction of the propulsion current in the propulsion winding along the guideway with the magnet system on the vehicle, for propulsion of the vehicle. It is still another object of the present invention to provide a MAGLEV vehicle position sensing system that operates in all weather conditions. It is another object of the present invention to provide a MAGLEV vehicle position sensing system that works at all operational speeds. Yet another object of the present invention is to provide a MAGLEV vehicle position sensing system which consumes low amounts of power, is easy to use, relatively simple to implement, and comparatively cost effective.